AudiForums.com

Go Back   AudiForums.com > Audi Models > Audi A4 > B5 Models
Sign in using an external account
Register Forgot Password?
Search

B5 Models Please discuss all 1996 - 2001 B5 A4 topics here...

Welcome to Audi Forums!
Welcome to Audi Forums,

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!


Reply
 
 
 
 
LinkBack Thread Tools Search this Thread
  #1  
Old 03-30-2011, 12:56 AM
1st Gear

 
Join Date: Mar 2011
Posts: 2
Question A4 1.8T cold start problem - low rpm

When my A4 B5 1.8T sits for 10 hours or longer, it needs quite a few cranks (10 seconds or so) until it starts. Even then, it starts slowly and rough.

When it was working fine, rpms would go higher in the first minute after a cold start, bu it no longer does that. Almost like a missing "choke" - or whatever the equivalent is for these engines.

Do you know what controls the rpm increase for a cold engine? What could cause them to stay low like it would be for a warm engine?

I already cleaned the MAF, replaced fuel filter + spark plugs. Temp display is fine otherwise, but I'll try replacing the sensor next.
  #2  
Old 03-30-2011, 10:09 AM
1st Gear
 
Join Date: Mar 2011
Location: Upstate NY
Posts: 50
Points: 814, Level: 15
Points: 814, Level: 15 Points: 814, Level: 15 Points: 814, Level: 15
Level up: 14%, 86 Points needed
Level up: 14% Level up: 14% Level up: 14%
Daily Activity: 2.4%
Daily Activity: 2.4% Daily Activity: 2.4% Daily Activity: 2.4%
Default

On the first start of the day mine idles low as well. Any other cold start (but not the first start in a long period of time such as an overnight) it will idle high, as it should, for about a minute.

No clue what this is all about either...
  #3  
Old 04-03-2011, 01:08 AM
1st Gear

 
Join Date: Mar 2011
Posts: 2
Default

Swapping out the coolant temp sensor fixed my cold start problem.

I didn't think it would since the temp gauge showed correct values, but maybe it's driven by another sensor.
  #4  
Old 04-03-2011, 02:58 PM
1st Gear

 
Join Date: Jan 2011
Posts: 206
Points: 3,016, Level: 33
Points: 3,016, Level: 33 Points: 3,016, Level: 33 Points: 3,016, Level: 33
Level up: 78%, 34 Points needed
Level up: 78% Level up: 78% Level up: 78%
Daily Activity: 0%
Daily Activity: 0% Daily Activity: 0% Daily Activity: 0%
Default

Does the idle surge?
What is a "high" idle for you?

Cold start mine will be about 850 all day long. Warm start again,850. My coolant temp gauge is shot and no starting problems.

I would definitely check the sensor governing the intake air temp and maybe check 02's? Could be something simple, could be...lol

Another thing to check are vacuum lines!!!
  #5  
Old 04-03-2011, 10:42 PM
foxracing4500's Avatar
1st Gear
 
Join Date: Jan 2011
Location: Lewistown, PA
Posts: 243
Points: 2,794, Level: 32
Points: 2,794, Level: 32 Points: 2,794, Level: 32 Points: 2,794, Level: 32
Level up: 30%, 106 Points needed
Level up: 30% Level up: 30% Level up: 30%
Daily Activity: 2.1%
Daily Activity: 2.1% Daily Activity: 2.1% Daily Activity: 2.1%
Default

shot in the dark but

Starter solenoid? Starter Motor? Loose wiring in the starting circuit?

Like wise, mine starts in 2-3 seconds and idles at 850 hot/cold
__________________
Project "Kleen" Cancelled, new project "survive to 300k Miles"
  #6  
Old 04-04-2011, 12:48 AM
1st Gear
 
Join Date: Jun 2006
Location: NyC - Manhattan
Posts: 228
Send a message via AIM to MilitantGrunt
Default

Replace the hall sender / crank position sensor. Usually when these sensors are cold, they have less electrical resistance, while warm they may function well but not when cold.
__________________
www.iWantToGoFast.net - DM Technik Long Island, NY.
-98.5 A4 1.8t - RIP
-01 A4 1.8t hta3076 - Engine RIP -> 2.7t Swap SOLD!
-95 UrS6 2.2t - Stock.. For now =).
  #7  
Old 04-04-2011, 01:23 AM
1st Gear

 
Join Date: Apr 2010
Posts: 203
Points: 2,229, Level: 28
Points: 2,229, Level: 28 Points: 2,229, Level: 28 Points: 2,229, Level: 28
Level up: 53%, 71 Points needed
Level up: 53% Level up: 53% Level up: 53%
Daily Activity: 2.7%
Daily Activity: 2.7% Daily Activity: 2.7% Daily Activity: 2.7%
Default

See if your suction pump is disconnected. Happened to me and caused starting problems.
  #8  
Old 04-04-2011, 01:32 AM
1st Gear
 
Join Date: Apr 2011
Posts: 5
Default

The rpm's are fine. It's just that if the engine is cold, you can floor it and get only a turtle crawl. Once warm, problem only occurs during wide turns.
__________________
android phone
China Wholesale
  #9  
Old 04-05-2011, 09:10 PM
1st Gear

 
Join Date: Jan 2011
Posts: 206
Points: 3,016, Level: 33
Points: 3,016, Level: 33 Points: 3,016, Level: 33 Points: 3,016, Level: 33
Level up: 78%, 34 Points needed
Level up: 78% Level up: 78% Level up: 78%
Daily Activity: 0%
Daily Activity: 0% Daily Activity: 0% Daily Activity: 0%
Default

During wide turns??????????

Fuel? does anyone else think it could possibly be a fuel pump?
How cold is it outside?

The turns thing is very confusing
Old 04-05-2011, 09:10 PM
 
 
 
Reply


Tags
18, 18t, a4, audi, b5, cold, coolant, location, power, problem, revs, rpm, sensor, shifts, start


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Advertising

Featured Sponsors
Vendor Directory
New Sponsors

All times are GMT -4. The time now is 02:54 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Internet Brands, Inc.
Emails Backup